There is a DM near us and one in the city that have many gluten free items.
There is an organic market called Tegut that is also very handy, and has MANY gluten free items that are prepackaged, flours and such. They even have hemp products!
I have found many more items to add to my pantry, including a few cereals for my bran muffin recipe.
There is an asian store in the city (Thai) and an Asian-Indian market in the city that has helped us greatly. In the city my DH works in, there is an asian market as well. He found all KINDS of things for me that we can't find at the two stores nearest to us.
So there's hope for Germany afterall, it just takes really learning the system and where to look for things.